Polyethyleneimine-modified layered double hydroxide/SBA-15 composites: A novel kind of highly efficient CO2 adsorbents

The SBA-15-supported polyethyleneimine (PEI)-modified layered double hydroxides ( x LDH- y PEI/SBA-15) were prepared by the in situ coprecipitation method, and their CO 2 adsorption performance and involved mechanisms were studied. After loading of PEI and LDH on the surface of SBA-15, the composite materials still maintained an ordered two-dimensional hexagonal porous structure . The optimal CO 2 adsorption capacity (2.01 mmol/g) of 40LDH-2PEI/SBA-15 at 50 °C was 1.88 times larger than that (1.07 mmol/g) of SBA-15. Such an excellent CO 2 adsorption capacity of 40LDH-2PEI/SBA-15 was associated with its high BET surface area, abundant basic sites, and fast adsorption kinetics . The regeneration efficiency of 40LDH-2PEI/SBA-15 was still 94% after 11 recycles. We are sure that the SBA-15-supported PEI-modified LDH materials are good performance adsorbents for the adsorption of carbon dioxide. The SBA-15-supported polyethyleneimine (PEI)-modified LDH ( x LDH- y PEI/SBA-15) composites are prepared by the co-precipitation and impregnation methods. The 40LDH-2PEI/SBA-15 sample possesses a large CO 2 adsorption capacity at 50 °C and excellent regeneration efficiency, and the adsorbed CO 2 is mainly stored in the forms of carbonate and bicarbonate. • A new type of LDH-PEI/SBA-15 composites as CO 2 adsorbent is prepared. • 40LDH-2PEI/SBA-15 exhibits excellent CO 2 adsorption performance at 50 °C. • In situ DRIFTS reveals that the adsorbed CO 2 is mainly stored in the forms of CO 3 2− and HCO 3 − . • 40LDH-2PEI/SBA-15 shows rapid adsorption kinetics and good regeneration efficiency.